Shank Assembly with a Tensioned Element

ABSTRACT

In one aspect of the invention, a tool comprises a head and a shank assembly. The shank assembly has a tensioned element axially disposed within a bore of a structural element and a distal end of the tensioned element is secured within or below the bore. The head has a cavity formed in its base end and is adapted to receive a proximal end of the tensioned element. The tensioned element has a radially extending catch adapted to interlock within the cavity of the head. The head is harder than the tensioned element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/971,965 which is a continuation of U.S. patent application Ser. No. 11/947,644, which was a continuation-in-part of U.S. patent application Ser. No. 11/844,586. U.S. patent application Ser. No. 11/844,586 is a continuation in-part of U.S. patent application Ser. No. 11/829,761. U.S. patent application Ser. No. 11/829,761 is a continuation-in-part of U.S. patent application Ser. No. 11/773,271. U.S. patent application Ser. No. 11/773,271 is a continuation in-part of U.S. patent application Ser. No. 11/766,903. U.S. patent application Ser. No. 11/766,903 is a continuation of U.S. patent application Ser. No. 11/766,865. U.S. patent application Ser. No. 11/766,865 is a continuation-in-part of U.S. patent application Ser. No. 11/742,304. U.S. patent application Ser. No. 11/742,304 is a continuation of U.S. patent application Ser. No. 11/742,261. U.S. patent application Ser. No. 11/742,261 is a continuation in-part of U.S. patent application Ser. No. 11/464,008. U.S. patent application Ser. No. 11/464,008 is a continuation in-part of U.S. patent application Ser. No. 11/463,998. U.S. patent application Ser. No. 11/463,998 is a continuation in-part of U.S. patent application Ser. No. 11/463,990. U.S. patent application Ser. No. 11/463,990 is a continuation-in-part of U.S. patent application Ser. No. 11/463,975. U.S. patent application Ser. No. 11/463,975 is a continuation-in-part of U.S. patent application Ser. No. 11/463,962. U.S. patent application Ser. No. 11/463,962 is a continuation-in-part of U.S. patent application Ser. No. 11/463,953. The present application is also a continuation in-part of U.S. patent application Ser. No. 11/695,672. U.S. patent application Ser. No. 11/695,672 is a continuation in-part of U.S. patent application Ser. No. 11/686,831. All of these applications are herein incorporated by reference for all that they contain.

BACKGROUND OF THE INVENTION

Brazes and welds that connect brittle materials, such as carbide, to metal tools often affect the integrity of the brittle material. Consequently, many efforts have been made to improve the way in which high impact surfaces are attached. Examples of such efforts are disclosed in U.S. Pat. No. 4,944,559 to Sionnet et al., U.S. Pat. No. 5,837,071 to Andersson et al., U.S. Pat. No. 5,417,475 to Graham et al., U.S. Pat. No. 6,051,079 to Andersson et al., and U.S. Pat. No. 4,725,098 to Beach, all of which are herein incorporated by reference for all that they contain.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the invention, a tool comprises a head and a shank assembly. The shank assembly has a tensioned element axially disposed within a bore of a collar and a distal end of the tensioned element is secured within or below the bore. The head has a cavity formed in its base end and is adapted to receive a proximal end of the tensioned element. The tensioned element has a radially extending catch adapted to interlock within the cavity of the head. The head is harder than the tensioned element.

The cavity may have an inwardly protruding catch. The inwardly protruding catch may be adapted to interlock with the radially extending catch. The inwardly protruding catch may be a hook, may be a taper, may form a slot, or combinations thereof. The radially extending catch may be a hook, may be a taper, may form a slot, or combinations thereof. An inside surface of the cavity may have a uniform inward taper.

An insert may be intermediate the inwardly protruding catch and the radially extending catch. The insert may be a ring, a snap ring, a split ring, or a flexible ring. The insert may be a plurality of balls, wedges, shims or combinations thereof. The insert may be a spring. The insert may be deformed under a pressure exerted on the tensioning element. The insert may comprise stainless steel. The insert may have a flat surface substantially normal to a central axis of the shank assembly.

The head may comprise a cemented metal carbide, polycrystalline diamond, cubic boron nitride, hardened steel, ceramics, zirconium, tungsten, silicon carbide, hardened metals, and combinations thereof. The base of the head may have an upward extending taper. The collar may have a seat complimentary to the base of the head. An interface between the base of the head and the seat may have a filler material. The head may have at least two segments jointed by a braze joint.

The tensioned element may have a clearance between its outer diameter and an inside surface of the bore. The distal end of the tensioned element may be secured within the collar by a tensioning mechanism. The tensioning mechanism may comprise a press fit, a taper, a spring, a threadform, and/or a nut. The tensioned element may be cold worked as tension is applied to the tensioned element.

The tool may be incorporated in drill bits, shear bits, percussion bits, roller cone bits or combinations thereof. The tool may be incorporated in mining picks, trenching picks, asphalt picks, excavating picks or combinations thereof. The tool may be incorporated into a flat surface, table top, or combinations thereof. The tool may be incorporated into mills, hammermills, cone crushers, jaw crushers, shaft impactors or combinations thereof. The tool may be packed tightly in groups of at least two tools.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of an embodiment of a milling machine.

FIG. 2 is a cross-sectional diagram of an embodiment of an impact resistant pick.

FIG. 2 a is a cross-sectional diagram of another embodiment of a pick.

FIG. 3 is a cross-sectional diagram of another embodiment of a pick.

FIG. 3 a is a cross-sectional diagram of another embodiment of a pick.

FIG. 4 is a cross-sectional diagram of another embodiment of a pick.

FIG. 5 is a cross-sectional diagram of another embodiment of a pick.

FIG. 6 is a perspective diagram of an embodiment of a wedge.

FIG. 7 is a cross-sectional diagram of another embodiment of a pick.

FIG. 8 is a cross-sectional diagram of another embodiment of a pick.

FIG. 9 is a cross-sectional diagram of another embodiment of a pick.

FIG. 10 is a perspective diagram of an embodiment of an insert.

FIG. 11 is a perspective diagram of another embodiment of an insert.

FIG. 12 is a perspective diagram of another embodiment of an insert.

FIG. 13 is a perspective diagram of another embodiment of an insert.

FIG. 14 is a cross-sectional diagram of another embodiment of a pick.

FIG. 15 is a cross-sectional diagram of another embodiment of a pick.

FIG. 16 is a cross-sectional diagram of another embodiment of a pick.

FIG. 17 is a cross-sectional diagram of another embodiment of a pick.

FIG. 18 is a cross-sectional diagram of an embodiment of a tool head.

FIG. 19 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 20 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 21 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 22 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 23 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 24 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 25 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 26 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 27 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 28 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 29 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 30 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 31 is a cross-sectional diagram of another embodiment of a tool head.

FIG. 32 is a perspective diagram of an embodiment of a shank assembly.

FIG. 33 is a cross-sectional diagram of an embodiment of a shank assembly and a head.

FIG. 34 is a cross-sectional diagram of another embodiment of a shank assembly and a head.

FIG. 35 is a cross-sectional diagram of another embodiment of a pick.

FIG. 36 is a cross-sectional diagram of another embodiment of a pick.

FIG. 37 is a cross-sectional diagram of an embodiment of a mining pick.

FIG. 38 is a cross-sectional diagram of another embodiment of a mining pick.

FIG. 39 is a perspective diagram of an embodiment of a tool assembly.

FIG. 40 is a perspective diagram of another embodiment of a tool assembly.

FIG. 41 is a perspective diagram of another embodiment of a tool assembly.

FIG. 42 is a cross-sectional diagram of another embodiment of a tool assembly.

FIG. 43 is a cross-sectional diagram of an embodiment of a drum.

FIG. 44 is a cross-sectional diagram of an embodiment of a table.

FIG. 45 is a perspective diagram of an embodiment of a drill bit.

FIG. 46 is a perspective diagram of another embodiment of a drill bit.

FIG. 47 is a perspective diagram of another embodiment of a drill bit.

FIG. 48 is a perspective diagram of another embodiment of a drill bit.

FIG. 49 is a perspective diagram of another embodiment of a drill bit.

FIG. 50 is a perspective diagram of an embodiment of a trencher.

FIG. 51 is a perspective diagram of another embodiment of a trencher.

FIG. 52 is a cross-sectional diagram of an embodiment of a roller assembly.

FIG. 53 is a perspective diagram of an embodiment a rotating drum attached to a mining machine.

FIG. 54 is a perspective diagram of an embodiment of a chisel.

FIG. 55 is a perspective diagram of another embodiment of a chisel.

FIG. 56 is a perspective diagram of an embodiment of a vertical shaft impactor.

FIG. 57 is a cross-sectional diagram of an embodiment of a jaw crusher.

FIG. 58 is a cross-sectional diagram of an embodiment of a hammer mill.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a cross-sectional diagram of an embodiment wherein the tool 100 is incorporated into a plurality of picks 101 attached to a driving mechanism 103, such as a rotating drum connected to the underside of a pavement milling machine 105. The milling machine 105 may be a cold planer used to degrade manmade formations such as a paved surface 104 prior to the placement of a new layer of pavement. Picks 101 may be attached to the driving mechanism 103 bringing the picks 101 into engagement with the formation. A holder 102, which may be a block, an extension in the block or a combination thereof, is attached to the driving mechanism 103, and the pick 101 is inserted into the holder 102. The holder 102 may hold the pick 101 at an angle offset from the direction of rotation, such that the pick 101 engages the pavement at a preferential angle. Each pick 101 may be designed for high-impact resistance and long life while milling the paved surface 104.

Referring now to FIG. 2, the pick 101 comprises a shank assembly 200 comprising a proximal end 201 and a distal end 202. The shank assembly 200 also comprises a head 235. The head 235 may comprise an impact tip 208 that is brazed to a carbide bolster 205. The bolster 205 is adapted to interlock with the shank assembly 200. The proximal end 201 of the shank assembly 200 may be press fit into a cavity 203 in a base end 204 of a cemented metal carbide bolster 205. A super hard material 206 may be bonded to a cemented metal carbide substrate 207 to form the impact tip 208, which may then be bonded to the bolster 205 opposite the base end 204 of the bolster 205, and opposite the proximal end 201 of the shank assembly 200. In FIG. 2 the shank assembly 200 is generally cylindrical. The distal end 202 of the shank assembly 200 is disposed within a recess 209 of a holder 102, which may comprise an extension 210, a block 211 attached to the driving mechanism 103, or both.

An outer surface of the holder 102 may comprise hard-facing in order to provide better wear protection for the holder 102. The hard-facing may comprise ridges after it is applied, though the ridges may be machined down afterward. In some embodiments a sleeve 228 is disposed intermediate the pick 101 and the holder 102. In some embodiments the base end 204 of the bolster 205 may be in direct contact with an upper face 213 of the holder 102, and may overhang the holder 102 and hard-facing, which may prevent debris from collecting on the upper face 213. The recess 209 of the holder 102 may comprise hard-facing. One method of hard-facing the recess 209 is case-hardening, during which process the recess 209 is enriched with carbon and/or nitrogen and then heat treated, which hardens the recess 209 and provides wear protection, although other methods of hard-facing the recess 209 may also be used. The shank assembly 200 is adapted to be retained within the recess 209.

The shank assembly 200 may comprise a hard material such as steel, stainless steel, hardened steel, or other materials of similar hardness. The bolster 205 may comprise tungsten, titanium, tantalum, molybdenum, niobium, cobalt and/or combinations thereof. The super hard material 206 may be a material selected from the group consisting of diamond, monocrystalline diamond, polycrystalline diamond, sintered diamond, chemical deposited diamond, physically deposited diamond, natural diamond, infiltrated diamond, layered diamond, thermally stable diamond, silicon bonded diamond, metal-bonded diamond, silicon carbide, cubic boron nitride, and combinations thereof.

The shank assembly 200 may be work-hardened or cold-worked in order to provide resistance to cracking or stress fractures due to forces exerted on the pick 101 by the paved surface 104 or the holder 102. The shank assembly 200 may be work-hardened by shot-peening or by other methods of work-hardening. The shank assembly 200 may also be rotatably held into the holder 102, such that the pick 101 is allowed to rotate within the holder 102. At least a portion of the shank assembly 200 may also be work-hardened by stretching it during the manufacturing process.

The shank assembly 200 comprises a tensioned element 214 and a collar 252. The tensioned element 214 is axially disposed within a bore 242 of the collar 252 and the distal end 202 of the tensioned element 214 is secured within or below the bore. The proximal end 201 of the tensioned element 214 protrudes into the cavity 203 in the base end 204 of the bolster 205 and the proximal end 201 of the collar 252 may be press fit into the cavity 203 in the base end 204 of the bolster 205. The tensioned element 214 is adapted to lock the proximal end 201 of the shank assembly 200 within the cavity 203. The tensioned element 214 may attach the shank assembly 200 to the carbide bolster 205 and restrict movement of the shank assembly 200 with respect to the carbide bolster 205. The tensioned element 214 comprises a radially extending catch 236 that is formed in the proximal end 201 of the shank assembly 200. The shank assembly 200 may be prevented by the tensioned element 214 from moving in a direction parallel to a central axis 403 of the pick 101. In some embodiments the shank assembly 200 may be prevented by the tensioned element 214 from rotating about the central axis 403.

In FIG. 2 the cavity 203 comprises an inwardly protruding catch 237. An insert 238 is disposed intermediate the inwardly protruding catch 237 of the cavity 203 and the radially extending catch 236 of the proximal end 201 of the tensioned element 214. In some embodiments the insert 238 is a flexible ring 239. In some embodiments the insert 238 may be a ring, a snap ring, a split ring, coiled ring, a flexible ring 239 or combinations thereof. In FIG. 2 the tensioned element 214 comprises a locking shaft 240. The locking shaft 240 is connected to an expanded locking head 241. In some embodiments the radially extending catch 236 is an undercut formed in the locking head 241. The insert 238 and locking head 241 are disposed within the cavity 203 of the carbide bolster 205. The locking shaft 240 protrudes from the cavity 203 and into an inner diameter 216 of the shank assembly 200. The locking shaft 240 is disposed proximate the bore 242 proximate the proximal end 201 of the shank assembly 200. The locking shaft 240 is adapted for translation in a direction parallel to the central axis 403 of the shank assembly 200. The locking shaft 240 may extend from the cavity 203 and the insert 238 may be inserted into the cavity 203.

When the proximal end 201 of the tensioned element 214 is inserted into the cavity 203, the locking head 241 may be extended away from the bore 242 of the collar 252. The insert 238 may be disposed around the locking shaft 240 and be intermediate the locking head 241 and the bore 242. The insert 238 may comprise stainless steel. In some embodiments the insert 238 may comprise an elastomeric material and may be flexible. The insert 238 may be a ring, a snap ring, a split ring, a coiled ring, a rigid ring, segments, balls, shims, a spring or combinations thereof.

Referring now to FIG. 2 a, the insert 238 may comprise a breadth 244 that is larger than an opening 243 of the cavity 203. In such embodiments the insert 238 may compress to have a smaller breadth 244 than the opening 243. Once the insert 238 is past the opening 243, the insert 238 may expand to comprise its original or substantially original breadth 244. With both the insert 238 and the locking head 241 inside the cavity 203, the rest of the proximal end 201 of the shank assembly 200 may be inserted into the cavity 203 of the bolster 205. Once the entire proximal end 201 of the shank assembly 200 is inserted into the cavity 203 to a desired depth, a nut 245 may be threaded onto an exposed end 246 of the locking shaft 240 until the nut 245 contacts a ledge 247 proximate the constricted inner diameter 242. This contact and further threading of the nut 245 on the locking shaft 240 may cause the locking shaft 240 to move toward the distal end 202 of the shank assembly 200 in a direction parallel to the central axis 403 of the shank assembly 200. This may also result in bringing the radially extending catch 236 of the locking head 240 into contact with the insert 238, and bringing the insert 238 into contact with the inwardly protruding catch 237 of the cavity 203. The nut 245 is an embodiment of a tensioning mechanism 247. The tensioning mechanism 247 is adapted to apply a rearward force on the proximal end 201 of the shank assembly 200. The rearward force may pull the proximal end 201 of the rear portion 200 in the direction of the distal end 202. In some embodiments the tensioning mechanism 247 may comprise a press fit, a taper, and/or a nut 245.

Once the nut 245 is threaded tightly onto the locking shaft 240, the locking head 241 and insert 238 are together too wide to exit the opening 243. In some embodiments the contact between the locking head 241 and the bolster 205 via the insert 238 may be sufficient to prevent both rotation of the shank assembly 200 about its central axis 403 and movement of the shank assembly 200 in a direction parallel to its central axis 403. In some embodiments the tensioned element 214 is also adapted to inducibly release the shank assembly 200 from attachment with the carbide bolster 205 by removing the nut 245 from the locking shaft 240.

In some embodiments the insert 238 may be a snap ring. The insert may comprise stainless steel and may be deformed by the pressure of the locking head 241 being pulled towards the distal end 202 of the shank assembly 200. As the insert 238 deforms it may become harder. The deformation may also cause the insert 238 to be complementary to both the inwardly protruding catch 237 and the radially extending catch 236. This dually complementary insert 238 may avoid point loading or uneven loading, thereby equally distributing contact stresses. In such embodiments the insert 238 may be inserted when it is comparatively soft, and then may be work hardened while in place proximate the catches 236, 237.

In some embodiments at least part of the shank assembly 200 of the pick 101 may also be cold worked. The tensioned element 214 may be stretched to a critical point just before the strength of the tensioned element 214 is compromised. In some embodiments, the locking shaft 240, locking head 241, and insert 238 may all be cold worked by tightening the nut 245 until the locking shaft and head 240, 241, and the insert 238, reach a stretching critical point. During this stretching the insert 238, and the locking shaft and head 240, 241, may all deform to create a complementary engagement, and may then be hardened in that complementary engagement. In some embodiments the complementary engagement may result in an interlocking between the radially extending catch 236 and the inwardly protruding catch 237.

In the embodiment of FIG. 2 a, both the inwardly protruding catch 237 and the radially extending catch 236 are tapers. Also in FIG. 2 a, the base end 204 of the bolster 205 comprises a uniform inward taper 248. The impact tip 208 in FIG. 2 a comprises a diamond 250 bonded to the carbide substrate 207. In some embodiments the diamond 250 may comprise a volume that is 75% to 175% of a volume of the carbide substrate 207.

The diamond is an embodiment of a superhard material 206 and comprises a generally conical shape with an apex 251. The thickness 249 of the diamond at the apex 251 may be 0.100 to 0.500 inches. The cemented metal carbide substrate 207 may comprise a height of 0.090 to 0.250 inches. The superhard material 206 bonded to the substrate 207 may comprise a substantially pointed geometry with an apex comprising a 0.050 to 0.160 inch radius. Preferably, the interface between the substrate 207 and the superhard material 206 is nonplanar, which may help distribute loads on the tip 208 across a larger area of the interface. The side wall of the superhard material may form an included angle with a central axis of the tip between 30 to 60 degrees. In asphalt milling applications, the inventors have discovered that an optimal included angle is 45 degrees, whereas in mining applications the inventors have discovered that an optimal included angle is between 35 and 40 degrees. A tip that may be compatible with the present invention is disclosed in U.S. patent application Ser. No. 11/673,634 to Hall and is currently pending.

The impact tip 208 may be brazed onto the carbide bolster 205 at a braze interface. Braze material used to braze the tip 208 to the bolster 205 may comprise a melting temperature from 700 to 1200 degrees Celsius; preferably the melting temperature is from 800 to 970 degrees Celsius. The braze material may comprise silver, gold, copper nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, phosphorus, molybdenum, platinum, or combinations thereof. The braze material may comprise 30 to 62 weight percent palladium, preferable 40 to 50 weight percent palladium. Additionally, the braze material may comprise 30 to 60 weight percent nickel, and 3 to 15 weight percent silicon; preferably the braze material may comprise 47.2 weight percent nickel, 46.7 weight percent palladium, and 6.1 weight percent silicon. Active cooling during brazing may be critical in some embodiments, since the heat from brazing may leave some residual stress in the bond between the carbide substrate 207 and the super hard material 206. The farther away the super hard material is from the braze interface, the less thermal damage is likely to occur during brazing. Increasing the distance between the brazing interface and the super hard material 206, however, may increase the moment on the carbide substrate 207 and increase stresses at the brazing interface upon impact. The rear portion 200 may be press fitted into the bolster 205 before or after the tip 208 is brazed onto the bolster 205.

Referring now to FIGS. 3-3 a, in some embodiments the insert 238 may be a coil spring. The coil spring insert 238 may be inserted into the cavity 203 by placing the coil spring insert 238 around the locking shaft 240 before inserting the locking shaft 240 into the bore 242. As the locking shaft 240 is inserted into the bore 242 the upper face 213 pushes the coil spring insert 238 into the cavity 203 intermediate the radially extending catch 236 and the inwardly protruding catch 237. It is believed that the coil spring insert 238 will be beneficial in that it may be easier to place in the cavity 203 than the before mentioned insert 238 geometries. The radially extending catch 236 may have a conically curved geometry. In other embodiments, the radially extending catch 236 may have a radius or a curved geometry. The upper face 213 may taper inward towards the bore 242 and downward towards the distal end 202.

Referring now to FIGS. 4-13, a variety of inserts 238 are disclosed. In FIG. 4, a flexible insert 238 is being inserted into the cavity 203 while the locking shaft and head 240, 241 are already inside the cavity 203. In FIG. 5, a wedge 501 is disposed within the cavity 203 intermediate the inwardly protruding and radially extending catches 237, 236. FIG. 6 discloses a perspective view of an embodiment of the wedge 501. In some embodiments of the invention, the insert 238 may be one or more wedges 501. One wedge 501 may be already present in the cavity 203 when the locking head 241 is inserted into the cavity 203. Additional wedges 502 may be inserted into the cavity 203 while the locking head 241 is already present in the cavity 203.

FIGS. 7-9 disclose top-view cross-sectional diagrams of carbide bolsters 205. In FIG. 7 the inwardly protruding catch 237 is visible. In FIG. 8 a plurality of wedges 501 are disposed on the inwardly protruding catch 237. In FIG. 9, a plurality of balls 901 is disposed on the inwardly protruding catch 237. The insert 238 may be a plurality of balls 901, wedges 501, shims, or combinations thereof.

FIGS. 10-13 disclose various embodiments of inserts 238. FIG. 10 discloses an insert 238 comprising a plurality of interlocked segments 1001. FIG. 11 discloses an insert 238 comprising a plurality of abutting segments 1101. FIG. 12 discloses an embodiment of an insert 238 that is a snap ring 1201. FIG. 13 discloses an embodiment in which the insert 238 is a ring 1301. In some embodiments the ring 1301 may be flexible.

FIGS. 14-19 disclose various embodiments of the tensioning mechanism 247. FIG. 14 discloses a pick 101 in which the tensioning mechanism 247 may comprise a retaining clip 1401 adapted to fit in an inset portion 1402 of the locking shaft 240. An interior surface 1403 of the collar 252 comprises a transition taper 1404 intermediate the bore 242 and the inner diameter 216. The retaining clip 1401 may be adapted to expand away from the central axis 403 of the pick 101. As the retaining clip 1401 expands it may press against the transition taper 1404, thereby causing a resultant tension on the locking shaft 240 directed towards the distal end 202 of the shank assembly 200.

FIG. 15 discloses a pick 101 in which the tensioning mechanism 247 may comprise a nut 245. The nut 245 may be threaded onto the exposed end 246 of the locking shaft 240. The nut 245 may be selected from a group consisting of hex nuts, Allen nuts, cage nuts, cap nuts or combinations thereof. The nut 245 disclosed in FIG. 15 is an Allen nut. The base of the bolster is also tapered which is adapted to fit complimentarily into a pick holder. Such a taper is believed to reduce the stress between the holder and the bolster as well as support the bolster under side loads.

FIG. 16 discloses a pick 101 in which the tensioning mechanism 247 may comprise a snap ring 1601 adapted to fit in an expanded diameter region 1602 formed in the inner diameter 216. The expanded diameter region 1602 may retain the snap ring 1601 from movement a long the central axis 403. The snap ring 1601 may be able to rotate within the expanded diameter region 1602 about the central axis 403. The snap ring 1601 may be internally threaded and adapted to receive the exposed end 246 of the locking shaft 240.

FIG. 17 discloses a pick 101 in which the tensioning mechanism 247 may comprise a spring 1701 disposed intermediate the nut 245 or snap ring 1701 and the bore 242. The spring 1701 may be disposed around the locking shaft 240.

FIGS. 18-31 disclose various embodiments of the head 235. The head 235 may comprise a generally rectangular cross-sectional geometry 1801 such as in the embodiment of FIG. 18. The head 235 may comprise at least two segments 1802 jointed by a braze joint. The base end 204 of the head 235 may taper inward towards the opening 243 of the cavity 203 such as in the embodiment of FIG. 19. The head 235 may comprise a trapezoidal cross-sectional geometry 2001 such as in the embodiment disclosed in FIG. 20. The head 235 may comprise a cylindrical body 2101 and a domed impact surface 2102 such as in the embodiment disclosed in FIG. 21. The head 235 may comprise a generally spherical geometry 2201 such as in the embodiment of FIG. 22. The head 235 may comprise a generally hexagonal cross-sectional geometry 2301 such as in the embodiment of FIG. 23. The head 235 may also comprise a generally octagonal cross-sectional geometry 2401 such as in the embodiment of FIG. 24. The head 235 may also comprise an elliptical geometry 2501 such as in the embodiment of FIG. 25. The base end 204 of the head 235 may comprise a protuberance 2502, knob, bump, or combinations thereof. Referring to the embodiment of FIG. 26, the base end 204 of the head 235 may also comprise a groove 2602, dimple, hollow or combinations thereof. The upper face 213 of the collar 252 may be adapted to accommodate the protuberance 2502 or groove 2602. The head 235 may also comprise a generally triangular geometry 2601. The base end 204 may curve inward towards the cavity 203 such as in the embodiment disclosed in FIG. 27. The cavity 203 may taper inward to the inwardly protruding catch 237 such as in the embodiment of FIG. 28. The head 235 may comprise a backing surface 2901 generally opposite the impact tip 208 or the impact surface such as in the embodiment in FIG. 29. The head 235 may also comprise a second backing surface 3001 such as in the embodiment disclosed in FIG. 30. The backing surface 2901 and the second backing surface 3001 may share an interface with the collar 252, the extension 210, the block 211, the holder 102, the driving mechanism 103 or combinations thereof. It is believed that as the head contacts a formation the backing surface 2901 and the second backing surface 3001 may provide support to the head 235 preventing bending displacement of the head 235 from occurring. Referring to the embodiment disclosed in FIG. 38, the head 235 may comprise a rounded body 3102 supporting a flat impact surface 3101 such as in the embodiment of FIG. 31. The impact tip 208 may be brazed to the impact surface 3101.

The head 235 may comprise a material selected from a group consisting of cemented metal carbide, polycrystalline diamond, cubic boron nitride, hardened steel, ceramics, zirconium, tungsten, and combinations thereof.

Referring now to FIGS. 32-34, an embodiment of a tensioned element 214 is disclosed. The tensioned element 214 comprises a radially extending catch 236. The cavity 203 of the carbide bolster 205 comprises an inwardly protruding catch 237. The tensioned element 214 also comprises a locking head 241 having a short diameter 3201 and a long diameter 3202. The short diameter 3201 is smaller than the opening 243 of the cavity 203 and allows the locking head 241 to be inserted into the cavity 203 while held at an angle 3203 to the central axis 403 of the pick 101. FIG. 34 discloses the locking head 241 fully placed within the cavity 203 and the locking shaft 240 positioned parallel to the central axis 403 of the pick 101. An enlarged view 3401 shows the radially extending catch 236 of the locking head 241 and the inwardly protruding catch 237 of the cavity 203 comprising complementary tapers 3402, 3403.

Referring now to FIGS. 35-36, embodiments are disclosed in which the inwardly protruding catch 237 of the cavity 203 is adapted to interlock with the radially extending catch 236 of the tensioned element 214 proximate the proximal end 201 of the shank assembly 200. In FIG. 35 an inwardly protruding catch 237 that forms a seat 3501 is disclosed. The seat 3501 is recessed from the rest of the inwardly protruding catch 237. In FIG. 36 the radially extending catch 236 of the locking head 241 is shown interlocked with the inwardly protruding catch 237 by being placed in the seat 3501.

Referring now to FIG. 37-38, an embodiment of a mining pick 3701 is disclosed. The mining pick 3701 comprises a steel body 3702 disposed intermediate the carbide bolster 205 and a steel shank 3705. The shank assembly 200 may comprise a tensioned element 214, a collar 252, the steel body 3702, and may continue to the distal end 202 of the pick 3701. The steel body 3702 comprises a central recess 3703, and a distal surface 3704 of the steel body 3702 is in contact with the base end 204 of the carbide bolster 205. The locking shaft 240 is disposed within the collar 252, and the collar 252 is press fit into the central recess 3703 of the steel body 3702. The collar 252 may also be brazed or otherwise connected to the steel body 3702. In some embodiments the locking head 241 may be inserted into the cavity 203 of the carbide bolster 205 before inserting the locking shaft 240 into the collar 252. In such embodiments the collar 252 may then subsequently be press fit into the steel body 3702, or the collar 252 may already be press fit into the steel body 3702. FIG. 38 discloses an embodiment wherein the collar 252 may comprise the steel body 3702 and the steel shank 3705. The collar 252 may also comprise the extension 210, the block 211 or combinations thereof.

Referring now to FIGS. 39-42, the tool 100 may be arranged in an array with at least two tools 100 forming a tool assembly 3901. FIG. 39 discloses an embodiment wherein the tool assembly 3901 comprises the at least two tools 100 disposed adjacent to each other such that the head 235 of each tool 100 is tightly packed against the head 235 of the neighboring tools 100 in the tool assembly 3901. The heads 235 of the tools 100 in the tool assembly 3901 may form a continuous working surface 3902. The heads 235 in the tool assembly 3901 may each comprise a hexagonal perimeter 3909. The tools 100 in the tool assembly 3901 may be packed such that they are not aligned one with the other but still form a continuous working surface 3902. The tool assembly 3901 may comprise heads 235 of differing geometries 4201. The differing geometries 4201 of the heads 235 may be complimentary so as to form a continuous working surface 3902.

Referring to FIG. 43, the tool 100 may be used in a rotating drum 4301. The shank assembly 200 of the tool 100 may be press-fitted into slots 4302 such that the head 235 is exposed. A plurality of tools 100 may be connected to the drum 4301 such that the outer surface 4303 of the drum 4301 is covered and protected by the heads 235 of the tools 100.

The tool 100 may be used in various applications. The tool 100 may be incorporated into a flat surface, table top or combinations thereof. FIG. 44 discloses an embodiment of a table 4401 that comprises a table top 4402. The table top 4402 comprises a tool assemble 3901 consisting of at least two tools 100. The tensioned elements 200 may be disposed with in a structurally element 2252 such as a plate which may be shared by the at least two tools 100. In other embodiments, the structurally element 2252 may be a plate, collar, ball, foundation, beam, support, or combinations thereof.

FIGS. 45-58 disclose various wear applications that may be incorporated with the present invention. FIG. 45 discloses a drill bit 4500 typically used in water well drilling. FIG. 46 discloses a drill bit 4600 typically used in subterranean, horizontal drilling. FIG. 47 discloses a roller cone drill bit 4700 typically used in downhole, subterranean drilling. FIG. 48 discloses a shear bit 4800 typically used in downhole, subterranean drilling. FIG. 49 discloses a percussion bit 4900 typically used in downhole subterranean drilling. These bits 4500, 4600, 4700, 4800, 4900 and other bits may be consistent with the present invention.

The tool 100 may be used in a trenching machine, as disclosed in FIGS. 50 through 52. Tools 100 may be disposed on a rock wheel trenching machine 5000 as disclosed in FIG. 50. Referring to FIG. 51, the tools 100 may be placed on a chain that rotates around an arm 5101 of a chain trenching machine 5100. The tool 100 may be disposed on a roller assembly 5200 that is mounted on a chain trenching machine 5100 or a rotating drum.

FIG. 53 is an orthogonal diagram of an embodiment of a coal trencher 5300. The tools 100 may be connected to a rotating drum 5301 that is degrading coal 5302. The rotating drum 5301 is connected to an arm 5303 that moves the drum 5301 vertically in order to engage the coal 5302. The arm 5304 may move by a hydraulic arm 5305, it may also pivot about an axis or a combination thereof. The coal trencher 5300 may move about by tracks, wheels, or a combination thereof. The coal trencher 5300 may also move about in a subterranean formation. The coal trencher 5300 may be in a rectangular shape providing for easy mobility about the formation.

Referring now to FIGS. 54-55, chisels 5400 or rock breakers may also incorporate the present invention. At least one tool 100 may be placed on the impacting end 5401 of a rock breaker with a chisel 5400 or moil geometry 5500.

Referring to FIG. 56, the tool 100 may also be incorporated into vertical shaft impactors 5600. The tools 100 may be used on the targets 5601 or on the edges 5602 and face 5603 of a central rotor 5604.

Referring to FIGS. 57-58, a jaw crusher 5700 may comprise a fixed plate 5701 with a wear surface and pivotal plate 5702 with another wear surface. Rock or other materials are reduced as they travel down the plates 5701, 5702. The tools 100 may be fixed to the plates 5701, 5702 and may be in larger size as the tools 100 get closer to the pivotal end of the pivotal plate 5702. Hammer mills 5800 may incorporate the tool 100 on the distal end 5801 of the hammer bodies 5802.

Other applications not shown, but that may also incorporate the present invention include rolling mills; cone crushers; cleats; studded tires; ice climbing equipment; mulchers; jackbits; farming and snow plows; teeth in track hoes, back hoes, excavators, shovels; tracks, armor piercing ammunition; missiles; torpedoes; swinging picks; axes; jack hammers; cement drill bits; milling bits; reamers; nose cones; and rockets.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A tool, comprising: a head and a shank assembly; the shank assembly comprising a tensioned element axially disposed within a bore of a collar and a distal end of the tensioned element is secured within or below the bore; the head comprising a cavity formed in its base end and adapted to receive a proximal end of the tensioned element; and the tensioned element comprising a radially extending catch adapted to interlock within the cavity of the head; wherein the head is harder than the tensioned element.
 2. The tool of claim 1, wherein the cavity comprises an inwardly protruding catch.
 3. The tool of claim 2, wherein the inwardly protruding catch is adapted to interlock with the radially extending catch.
 4. The tool of claim 2, wherein an insert is intermediate the inwardly protruding catch and the radially extending catch.
 5. The tool of claim 4, wherein the insert is a ring, a snap ring, a split ring, or a flexible ring.
 6. The tool of claim 4, wherein the insert is a plurality of balls, wedges, shims or combinations thereof.
 7. The tool of claim 4, wherein the insert is a spring.
 8. The tool of claim 4, wherein the insert is deformed under a pressure exerted on the tensioning element.
 9. The tool of claim 4, wherein the insert comprises a stainless steel.
 10. The tool of claim 2, wherein the inwardly protruding catch is a hook, is a taper, forms a slot, or combinations thereof.
 11. The tool of claim 1, wherein the radially extending catch is a hook, is a taper, forms a slot, or combinations thereof.
 12. The tool of claim 1, wherein the head comprises a cemented metal carbide, polycrystalline diamond, cubic boron nitride, hardened steel, ceramics, zirconium, tungsten, silicon carbide, hardened metals and combinations thereof.
 13. The tool of claim 1, wherein the base of the head comprises an upward extending taper.
 14. The tool of claim 1, wherein the collar comprises a seat complimentary to the base of the head.
 15. The tool of claim 14, wherein an interface between the base of the head and the seat comprises a filler material.
 16. The tool of claim 1, wherein the distal end of the tensioned element is secured within the collar by a tensioning mechanism.
 17. The tool of claim 16, wherein the tensioning mechanism comprises a press fit, a taper, a threadform, a spring and/or a nut.
 18. The tool of claim 1, wherein an inside surface of the cavity comprises a uniform inward taper.
 19. The tool of claim 1, wherein the insert comprises a flat surface substantially normal to a central axis of the shank assembly.
 20. The tool of claim 1, wherein the head comprises at least two segments jointed by a braze joint.
 21. The tool of claim 1, wherein the tensioned element comprises a clearance between its outer diameter and an inside surface of the bore.
 22. The tool of claim 1, wherein the tool is incorporated in drill bits, shear bits, percussion bits, roller cone bits or combinations thereof.
 23. The tool of claim 1, wherein the tool is incorporated in mining picks, trenching picks, asphalt picks, excavating picks or combinations thereof.
 24. The tool of claim 1, wherein the tool is incorporated into a flat surface, table top, or combinations thereof.
 25. The tool of claim 1, wherein the tool is incorporated into nills, hammermills, cone crushers, jaw crushers, shaft impactors or combinations thereof.
 26. The tool of claim 1, wherein the tensioned element is cold worked as tension is applied to the tensioned element.
 27. The tool of claim 1, wherein the tool is packed tightly in groups of at least two tools.
 28. A tool, comprising: a head and a shank assembly; the shank assembly comprising a tensioned element axially disposed within a bore of a structurally element and a distal end of the tensioned element is secured within or below the bore; the head comprising a cavity formed in its base end and adapted to receive a proximal end of the tensioned element; and the tensioned element comprising a radially extending catch adapted to interlock within the cavity of the head; wherein the head is harder than the tensioned element. 